Table of Contents
- What is Metronidazole?
- Conditions Treated with Metronidazole
- Forms and Administration
- How Metronidazole Works
- Effectiveness of Metronidazole
- Possible Side Effects
- Ongoing Research
What is Metronidazole?
Metronidazole is an antibiotic medication used to treat various bacterial and parasitic infections. It is known by several brand names, including Flagyl[1]. Metronidazole works by killing or stopping the growth of certain bacteria and parasites that cause infections in your body[2].
Conditions Treated with Metronidazole
Metronidazole is used to treat a wide range of conditions, including:
- Bacterial vaginosis: An infection of the vagina caused by an overgrowth of certain bacteria[3]
- Complicated intra-abdominal infections: Infections inside the abdomen, often following surgery or injury[4]
- Clostridium difficile associated diarrhea (CDAD): A type of diarrhea caused by a specific bacteria, often after taking other antibiotics[5]
- Helicobacter pylori infection: A bacteria that can cause stomach ulcers[6]
- Periodontal diseases: Infections of the gums and other structures around the teeth[7]
- Crohn’s disease: A type of inflammatory bowel disease (in some cases, as part of combination therapy)[8]
Forms and Administration
Metronidazole comes in several forms, including:
The dosage and duration of treatment depend on the specific condition being treated and can vary from a single dose to several weeks of treatment[2][5].
How Metronidazole Works
Metronidazole belongs to a class of drugs called nitroimidazoles. It works by entering the cells of bacteria and parasites. Once inside, it is converted into compounds that damage the genetic material (DNA) of the microorganisms. This prevents them from making new DNA and ultimately leads to their death[2].
Effectiveness of Metronidazole
Clinical trials have shown that metronidazole is effective for treating various infections:
- For bacterial vaginosis, metronidazole vaginal gel has been shown to be effective in curing the infection in many women[3].
- In complicated intra-abdominal infections, metronidazole (when combined with other antibiotics) has demonstrated high cure rates[4].
- For Helicobacter pylori infections, metronidazole is often part of a combination therapy that has shown good eradication rates[6].
- In treating Clostridium difficile associated diarrhea, metronidazole has been a standard treatment, although newer options are also being studied[5].
Possible Side Effects
Like all medications, metronidazole can cause side effects. Common side effects may include:
- Nausea
- Diarrhea
- Metallic taste in the mouth
- Headache
More serious side effects are rare but can occur. It’s important to discuss potential side effects with your healthcare provider[2][5].
Ongoing Research
Researchers continue to study metronidazole to understand its effects better and explore new uses:
- Studies are looking at different formulations of metronidazole, such as delayed-release forms, which may increase the concentration of the antibiotic in the colon for treating certain infections[5].
- Researchers are investigating the use of metronidazole in combination with other antibiotics for treating conditions like Crohn’s disease in children[8].
- Scientists are also studying how metronidazole affects the body’s iron levels, which could have implications for its long-term use[6].


